1. Field of the Invention
The present invention relates to a magnetic test apparatus. More specifically, the present invention relates to a magnetic test apparatus for testing brushes and brush holders in the presence of a magnetic field.
2. Discussion of the Related Art
Evaluation of multi-conductor metallic brushes for electric propulsion motors and generators is important in assuring reliable operation of the motors, generators and vehicle or vessel they are utilized with. The complex operational environment of a large number of brushes can be simulated by a computer program, however, it is preferable that the computer results be validated by laboratory testing. Additionally, brushes can be evaluated after being actually used in a motor, however, these brushes are not easily accessible. Furthermore, it is not practical, in many instances to disassemble the motor during use in order to evaluate the brushes. Previously, brushes have been evaluated using a test apparatus that includes a motor driven rotor. The brushes are held in contact with the rotor the wear on the brushes can be evaluated. However, this type of test apparatus lacks many real world operating conditions.
Motors and generators can be subjected to high magnetic field strengths and varying environmental conditions while in use. These high varying magnetic fields and varying environmental conditions that can be present in electric propulsion motors and generators create a need for an apparatus to simulate the conditions of the motors and generators. Thus, there is a need for a measurement apparatus for testing brushes and brush holders under varying magnetic fields and environmental conditions.